Indiana doctor Anthony Garcia is suspected of being a serial killer, police said after taking him into custody in connection to four murders they believe may have been revenge killings.

Authorities say Garcia was fired as a pathology resident at Creighton University in Omaha for erratic behavior in 2001 by Dr. Roger Brumback and Dr. Thomas Hunter. Then, in 2008 Hunter's housekeeper and his 11-year-old son were found murdered inside his home. In May 2013, Brumback and his wife were also found murdered inside their home.

According to police, evidence proves Garcia - who hasn't lived in Nebraska since his residency - visited the city of Omaha during both of those killings.